<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    function study() {
        let num1=prompt("请输入第一个数");
        let num2=prompt("请输入第二个数");
        let num3=prompt("请输入运算符");
        let a1=parseInt(num1);
        let b1=parseInt(num2);
        if(num3=="+"){
            num3=a1+b1;
            document.write(+a1+"+"+b1+"="+num3);
        }else if(num3=="-"){
            num3=a1-b1;
            document.write(+a1+"-"+b1+"="+num3);
        }else if(num3=="*"){
            num3=a1*b1;
            document.write(+a1+"*"+b1+"="+num3);
        }else if(num3=="/"){
            num3=a1/b1;
            document.write(+a1+"/"+b1+"="+num3);
        }else{
            document.write("亲！输错了哟！！！")
        }
    }
    study()
</script>

</body>
</html>